Production of metallic tungsten.



F. G. KEYES & R. B. BROWNLEE. PRODUCTION OF METALLIC TUNGSTEN.

APPLICATION FILED JULY 5- 1914.

Patented Oct. 24, 1916.

ATTORNEY UNITED STATES PATENT OFFICE- FREDERICK G. KEYES AND ROBERT B.BROWNLEE, OF EAST ORANGE, NEW JER EY,

ASSIGNORS TO COOPER HEWITT ELECTRIC COMPANY, OF HOBOKEN, NEW Il'ERSEY, ACORPORATION OF NEW JERSEY.

PRODUCTION OF METALLIC TUNGSTEN.

1,202,534. Specification of Letter-S Yatent- Patented Oct. 24, 1916.

Application filed July 6, 1914. Serial No. 849,137. To all whom it mayconcern: actor of the deposit desired, the dimensions Be it known thatwe, FREDERICK G. KEYES of the bath, the volume of the electrolyzing andRoman? B. Bnowunuu, citizens of the fluid, and the area ofthe-electrodes. The

United States, and residents of East Orange, crucible itself should beof tungsten or high 55 5. county of Essex, St. te of New Jersey, havemelting alloy of tungsten that 15, it should invented certain new anduseful Tmprovebe of such a character as not to contaminate ments in theProduction of Metallic Tungthe bath with impurities if it is desired tosten, of which the following is a specificaproduce pure tungsten. Ihowever, it be desired to produce, for example. a car on- 60 tion.

The attempt to produce metallic tungsten bearing deposit, the cruciblematerial may by electrolytic processes has hitherto shown contain.carbon.

very meager results. It has been found, for In order to bring theelectrolytic subexample, that it is impossible to obtain stance into afluid condition, and to maintungsten electrolytically from an aqueoustain it in such condition during the electro- 65 solution of its salts.It has also been found lyzing process, use is made of the fact that thatonly the so-called tungsten-bronzes can the substance conductselectricity when col be obtained from molten para-tungstates. and mayconsequently carry current enough Moreover,- while we have found thattungto bring it to a fluid condition through the sten tri-oxld gives aclear solution in bone action of the PR heat or Joule heat. As- 70 acidat 1.000 to 1200 degrees centigrade, even sunung that the lower oxidformed b the with a high concentration of the tri-oxid, initial igntionabove referred to isW ,we yet such a solution submitted to a tensionknow that the heat of formation of this oxid of from 110 to 500 volts attemperatures is 131,000 calories per gram molecule; hence,

from 1000 to 1300 degrees centigrade perabout one volt is thedecomposition or depo- 75 units only a fraction of an ampere to pass.sition potential. Suflicient energy m add1- Separation of tungsten tookplace when the tion to this must be applied to maintain the electrolyticaction was prolonged, but the mater al in a fluid condition. process wasnecessarily slow and, for that Recapitulating the foregoing descriptionreason, was temporarily cast aside. Similar of the novel process heremdescribed, the 80 results were obtained with a solution of stepsconslst, first, of a. more or less protungsten oxy-chlorid in fusedboric acid. "A longed ignitionof W0 at 1800 to 2000 depracticalprocess'of producing metallic tunggrees centigrade. This results in thebsten is found, .however, by igniting for a eration of a portion of theoxygen, leaving more or less prolon ed period WO at 1800 a lower oxygencompound or a mixture of 85 to 2000 degrees C. Under these conditionssuch oxygen compounds. Thus, the first the liberation of oxygen takesplace, resultstep in the process may leave or ing in the formation oflower oxids of tungor a mixture of these two oxids. The substen and theproduction of a dark blue crysstance resulting from this part of theproctalline substance which conducts electricity ess is then brought toa fluid state and mam- 90 readily at ordinary temperatures. Thesubtained in said state, preferably by means 0 stance is fluid at about2000 degrees centithe PR heat, and a surplus of energy is apgrade and inits fluid condition mav be'utiplied to the material for maintaining itin a lived as an electrolytic bath from which mefluid condition. Theapplication of electric tallic tungsten can be separated'by theobcurrent to this fluid material causes a com- 95 servance of a propermode of procedure. pact deposit of metallic tungsten upon the In generalwe prefer to employ a rotatcathode. As already stated, the cathode ising cathode of tungsten and an anode in the of tungsten, and preferablya rotating cathform of a sintered rod of-tungsten, through ode, whilethe anode 1s, for example, a tungwhich and through the oxid bath anelectric sten anode consisting of a sintered rod of 10 current ispassed. Varying current 'densltungsten. The density of the currentapties may be employed according to the charplied to the bath'variesaccording to conditions already stated. It has been found that swa eddown to a diameter where it is pracat high temperatures anodes of highmelting tica to reduce the diameter still further by metals, as iridium,become oxid1zed at the drawing dies.

anode in this bath since oxygenis liberated, Plalnly, the processdescribed herein may and that, moreover, such oxid passing into beutilized for re ng. a metal or for ohthe solution, the metal ion isdeposited upon taming a metal from its soluble salts. There the Cathode,thereby producing an a1loy,or Is no istlnctlon, so far as thenaturepfthe at any rate, contaminating the deposit" of process goes. Thecase of tungsten, 1f that pure tungsten which it is desired to obtain.be the metal'sought to be thrown down by 1 course, an ideal electrodewould consist t e present process, is completely analogous f a ast barof lower tungsten oxids since to the well-known copper process, whereinan anode bar. Obviously, such an anode or, rloxld may e utillzed asanodes.

they conduct the electric current with facopper is obtained from itssoluble salts by cility. Asa matter of course, the melting usmg amagnetic anode or a platinum anode point of such an oxid would be thesame as in a splutionpf copper or wherein an electhe bath in which theelectrolysis is being trolytlc refining of copper 1s obtained by 8carried out and hence the use of such an means of an impure copper barused as an anode is precluded. The melting point of anode.

the anode, however, may be adjusted by mixv For certam p rpose 1t isdesirable to obing thelower tungsten oxid and tungsten tain very puretungsten and to this end bars powder and casting this into the form ofpressed up from partially reduced tungsticat least the particlesof tunten co osing obvious. that a pressed bar, even of pure it, will beattacked by th anion, the metal, would not be homogeneous, whereaspresent instance oxygen, forming oxid in an electrolytically disposedmetal would of deposit desired.

' posit of considerable thickness of metallic all probabilityand'thereby, becoming a pornecessity be homogeneous. "I would be postionof the bath itself. Thiszis desirable ,sible to use a pressed bar of Owhich has and forms as will be readily perceived, a a sufficiently 'ghmelting point but it is means of renewing the electrolytic bath.- moreconvenient to reduce tungsten trioxid her anodes, of course, may be.used deto the point where it contains enou h lower pending upon thecharacter of the cathode oxid to increase the melting point a vs thetemperature at which it is to be used asan I t is convenient to use asthe cathode a anode. Usually, intbis case, a small amount tungsten w reabout one-Sixteenth of an inch of metal will be present in the resultingin diameter. The first .Wire' -used in the powder. It is, of course,possible to reduce. formatlon of subsequent 11 wires may 11 with carboin the electric furnace, of iridium, 'for example, and after a deand resand sinter this material intobars t h be f d1 .will serve 21s anodes.ailiyelec ungsten as en orme upon this iri "um tro ytic' proces or eve'e uiva cut .0 wire the ngot thus created may be swaged el ctrochemicalmaterial dgosi ed upon thedown and a art of the wire again cathode, thesame electrochemical equivalent 9 asacat ode. By repeatingthisprocessmust be taken from the bath or from the ate and a pure anode. tungstenwire to form the cathode is ob- In the foregoing s ification we havetained. stated that it is deslrab e that the cathode be It will be undrstoed'that we have mencaused to rotate. The ob ect of this scarcely 9 toned the use o fan orlgmal iridium cathode requires explanation, but itwill be under- After the iridium has een of rotation will tend to keepthe bath in an remov b berapeated operations such as have activecondition with. a mare or less free'cirn descn wires or other sha of ourgradeor quality of ngste may bf utilized 'We have Illustrated the meansfor rotatas cathodes. There is, of course, no' conmg thecathode in theaccompan g draw-. trolling reason why ordinary commercial ing which is avertical seeltion o a tubular if fiesimd if'suited tmpeciall n ds or rere located the anode and the cathode of the 'quirements'. Whensufiiczent tungsten has syste been deposited upon the cathode, the wiref The furnace itself is shown at 1 and the mayjbe removed and anothersubstituted.- In crucible inside the furnace at 2. Within the practice,to prevent the bath from-coolin it crucible is the electrolytic bath 8alread is recommended to use two rotating cathodes, described. Thecrucible is subjected to very one of which may be: removed and a newhightemperature and must be of very recathod'e plaeed 1 n the 'ectrodeholder. The iractory material, preferably tungsten. It

el c, with its deposit, 18 then isnot that the crucible bemade of of thetransformer,

pure tungsten, although the material employed for the crucible should besuch as would not contaminate the bath containe in it. A support 4sustains the crucible as shown.

The anode of the bath appears at 5, and the cathode at 6. Both areconnected by an electric circuit, the opposite terminals 0 which run toa storage battery 7.

It has been stated that it was of advantage to have the cathode rotateduring operation. This is accomplished by means of a pulley having a Vshaped groove and a hearing, together with an independent operatingdriving motor. The bearing is shown at 8, the pulley at 9, and thedriving motor at 10, the pulley and driving motor being connected by aband 11. Because of the high temperature of the ba h, it is preferableto mount this pulley bearing and the driving mechanism therefor at apoint well remove from the surface of the crucible.

As to the details of the furnace, the same is preferably made ofgraphite and is provided with enlargements l2 and 13, through whichconnection is made to the terminals either with or without f bands 14and 15 of metal surrounding the enlargethe intervention 0 or otherconductor ments.

The primary of the transformer forming the direct means for energizingthe furnace, is shown at 16 and four coils 17 17 arranged in parallel,constitute the secon ary of t e primary 16, and are connected to thefurnace at 14 and 15. The drawing shows practically the entire systemdescribed herein.

We claim as our invention:

1. The method of producing pure tungsten which consists in bringing anoxi of tunguid condition in an inert environment, maintaining the saidcondition by Joule heat, and separating the tungsten from theelectrolyzing bath by an electrolytic process.

2. The method tungsten sten trioxid to a temperature of approximatelyN00 degrees centigrade,thereby producinga lower oxid or mixture of oxidsconductive of electricity and also thereby bringing the resultantsubstance to a fluid condition, maintaining such a condition and passingan electric current therethrough.

3. An electrolytic apparatus comprising a bath of fluid oxid oftungsten, a rotating tungsten cathode and a highly refractory anode.

4. In a fused electrolyzing bath, a cathode of pur tungsten and an anodeconsisting of a sintered rod of pure tungsten.

Signed at New York in the county of New York and State of New York this3rd day of July, A. D. 1914 FREDERICK G. KEYES. ROBT. B. BROWNLEE.

of separating metallic Witnesses Tnos. W. Bnown.

which consists in subjecting tung-

